First of all, space is a vacum, and if you put a liquid into a vacum it will goil to a gas really fast.
To answer your question, if you were to open the door on a space craft while in space and you did not have on a space suit, you would be dead before you can step out side the space craft.
This might be a little grusom, but this is what would take place in your body.
First your blood contains liquid and gas, as the out side pressure gets less, the Oxygen and Co2 in your blood would turn into gas bubbles and expand, then the liquid that your blood is made up of will boil to a gas, then the blood vesles in your body would explode, starting with the weakest blud vesles, in a few seconds you would look like you have been beaten all over your body with the back of a meat cleaver.
Here on Earth some Vets use vicum chambers to put pets to sleep.
They put the pet into a tank, close the door, then pull a vacum on another larger tank, then when the valve between the tanks are opened fast, the pet is bead in less than a second, in other words, that is how fast a person would die in in space with out a space suit.
The reason for wearing a space suit is so the air around your body is unser pressure.
On Earth at sea level the pressure is about 14.7 psi, in space your pressure suit keeps your outside pressure about 3 to 4 psi.
Bedore the people can leave the space craft in their space suits, the have to breath 100 per cent qxygen to get all the nitrogen out of their bodies, if they did not do this, when the step out of the space craft into the 3 to 4 psi pressure of their suits, they would get the bends just like a diver coming up from depth to fast.
Don't mind some of the miss spelt words, I have little time this morning.